From the Guidelines
Treatment for dimethoate poisoning requires immediate medical attention, with the cornerstone of treatment being atropine, starting with 1-2 mg IV, doubled every 5 minutes, and pralidoxime 1-2 g IV initially, followed by 400-600 mg/hour, as recommended by the 2023 American Heart Association guidelines 1. The management of dimethoate poisoning involves several key steps:
- Decontamination: removing contaminated clothing and thoroughly washing the skin with soap and water to prevent further absorption.
- Administration of atropine: to block parasympathetic overstimulation, mitigating bronchorrhea, bradycardia, bronchospasm, and CNS effects, with doses often required to be higher than for typical bradycardia, as indicated in the guidelines 1.
- Administration of pralidoxime: to reactivate the acetylcholinesterase enzyme before permanent binding ("aging") occurs, with a recommended dose of 1-2 g IV initially, followed by 400-600 mg/hour 1.
- Supportive care: maintaining airway, breathing, and circulation, with mechanical ventilation if needed, and monitoring fluid and electrolyte balance closely.
- Benzodiazepines: such as diazepam, may be used to control seizures and agitation, as suggested by the guidelines 1. It is essential to note that early and effective treatment may prevent deterioration to respiratory and cardiac arrest, and that atropine does not block acetylcholine excess at the neuromuscular junction or nicotinic ganglia, and therefore does not reverse paralysis, as stated in the guidelines 1.
From the FDA Drug Label
DOSAGE AND ADMINISTRATION Organophosphate Poisoning Treatment should include general supportive care, atropinization, and decontamination, in addition to the use of PROTOPAM Chloride. Treatment is most effective if initiated immediately after poisoning. Administration of PROTOPAM Chloride should be carried out slowly and, preferably, by infusion If intravenous administration is not feasible, intramuscular or subcutaneous injection should be used. Generally, little is accomplished if PROTOPAM Chloride is given more than 36 hours after termination of exposure to the poison When the poison has been ingested, it is particularly important to take into account the likelihood of continuing absorption from the lower bowel since this constitutes new exposure and fatal relapses have been reported after initial improvement. In such cases, additional doses of PROTOPAM Chloride may be needed every three to eight hours In effect, the patient should be “titrated” with PROTOPAM Chloride as long as signs of poisoning recur. As in all cases of organophosphate poisoning, care should be taken to keep the patient under observation for at least 48 to 72 hours. If dermal exposure has occurred, clothing should be removed and the hair and skin washed thoroughly with sodium bicarbonate or alcohol as soon as possible Supportive care, including airway management, respiratory and cardiovascular support, correction of metabolic abnormalities, and seizure control, may be necessary in cases of severe organophosphate poisoning. Atropine should be given as soon as possible after hypoxemia is improved Atropine should not be given in the presence of significant hypoxia due to the risk of atropine-induced ventricular fibrillation. In adults, atropine may be given intravenously in doses of 2 to 4 mg. This should be repeated at 5- to 10-minute intervals until full atropinization (secretions are inhibited) or signs of atropine toxicity appear (delirium, hyperthermia, muscle twitching) Some degree of atropinization should be maintained for at least 48 hours, and until any depressed blood cholinesterase activity is reversed. Use of morphine, theophylline, aminophylline, reserpine, and phenothiazine-type tranquilizers should be avoided in patients with organophosphate poisoning
The treatment for dimethoate poisoning includes:
- General supportive care
- Atropinization: atropine should be given as soon as possible after hypoxemia is improved, in doses of 2 to 4 mg, repeated at 5- to 10-minute intervals until full atropinization or signs of atropine toxicity appear
- Decontamination: clothing should be removed and the hair and skin washed thoroughly with sodium bicarbonate or alcohol as soon as possible
- Administration of PROTOPAM Chloride: should be carried out slowly and, preferably, by infusion, with additional doses needed every three to eight hours if signs of poisoning recur 2
- Supportive care: including airway management, respiratory and cardiovascular support, correction of metabolic abnormalities, and seizure control, may be necessary in cases of severe organophosphate poisoning It is essential to initiate treatment immediately after poisoning and to maintain observation for at least 48 to 72 hours 2.
From the Research
Dimethoate Poisoning Treatment
- Dimethoate poisoning is a life-threatening condition that requires immediate treatment, including decontamination and administration of antidotes such as atropine and pralidoxime (2-PAM) 3, 4.
- Skin decontamination is the primary intervention needed in cases of chemical exposure, and it can be achieved through washing with soap and water or water only 5, 6.
- However, traditional washing procedures may not be completely effective, and contaminants left on the skin after decontamination can have toxic consequences 5, 6.
- In cases of severe dimethoate poisoning, patients may present with hypotension, which can progress to shock and death despite treatment with atropine, intravenous fluids, and pralidoxime chloride 7.
- High-dose atropine therapy and early intervention may improve outcomes in patients with severe organophosphate poisoning, including dimethoate poisoning 3, 4.
- Novel treatment approaches, such as hemofiltration and lipid solutions, have been studied in recent years, but their effectiveness in treating dimethoate poisoning is not well established 4.
- Continuous cardiac monitoring and quantification of troponin T may be useful in diagnosing and managing dimethoate poisoning, but further studies are needed to establish their role in therapy 7.